Chip production and plywood veneer manufacture

ABSTRACT

The invention relates to the production of high quality wood chips as a by-product in the manufacture of plywood veneer. The natural outer layer of a log is chipped until the log has a substantially true cylindrical surface whereby an acceptable sheet of veneer can be produced therefrom without waste. The chips produced are suitably for pulp production.

United States Patent Logan 1 1 Aug. 15, 1972 [s41 CHIP PRODUCTION ANDPLYWOOD [56] References Cited VENEER MANUFACTURE UNITED STATES PATENTS[721 lnvemofl Kenneth 2 Quebec City, 2,695,044 11/1954 Miller et al...144/209 x Q Canada 3,152,626 10/1964 Nicholson ..144/209 X 3 324 9096/1967 McCranie ..144/326 [73] Ass1gnee. Anglo Paper Products Llnuted,

Quebec City, Quebec, Canada 228,899 6/1880 Holmes a ..144/209 X [22]Filed: April 6, 1970 Primary Examiner-Donald R. Schran pp No: 25,781 1Attorney-Wen, Marshall, MacRae& Lamb [57] ABSTRACT Cl 4/ /2 R, 144/326R, The invention relates to the production of high quality 7 144/208 G,144/ 162 R, 144/3 R wood chips as a by-product in the manufacture of[51] Int. Cl ..B27l11/02, B271 5/02 plywood veneer. The natural outerlayer of a log is 58 Field of Search ..144/209 T, 162, 309, 3, 208,chipped until the a has a Substantially true cylindri- V 14 32 calsurface whereby an acceptable sheet of veneer can be produced therefromwithout waste. The chips produced are suitably for pulp production.

2 Claims, 2 Drawing Figures PATENTEU M19 15 1973 3 683, 983

INVENTOR BY v p PATENT AGENT CHIP PRODUCTION AND PLYWOOD VENEERMANUFACTURE This invention relates to the production of high qualitychips as a by-product in the manufacture of plywood veneer.

In the manufacture of plywood veneer, a log of wood is turned against aknife extending across the length of the log. As the log turnsand thewood contacts the knife edge, a thin sheet of veneer is peeled off in along, continuous ribbon of wood. Since the outer surface of the log isnot perfectly circular in cross-section, the veneer produced at thebeginning of the peeling operation is not uniform in thickness andcannot be used in the manufacture of plywood. Instead, it is usuallydiscarded as waste veneer. This waste veneer is broken up into fragmentswhich are then chipped to produce wood chips for pulping or particleboard manufacture. The intermediate breaking operation causessubstantial damage to the wood and leads to the production of poorquality chips.

The present invention seeks to eliminate the intermediate step ofbreaking up the waste veneer and to directly produce good quality. woodchips from logs used in the manufacture of plywood veneer.

The invention resides in a method and apparatus for producing goodquality wood chips from the waste portion of logs to be used in'themanufacture of plywood veneer. To this end, the natural outer layer of alog is directly engaged by a chipping knife assembly to produce suchchips. The chipping operation is continued until a substantially truecylindrical surface is formed on the log, when 'it is discontinued andthereafter a veneerblade applied to. the cylindrical sur- I faceproduces an acceptable sheet of veneer.

The invention will be described with reference to the accompanyingdrawing, in which FIG. 1 is an end elevation of an apparatus inaccordance with the invention, and

FIG. 2 is a schematic view illustrating theoperative steps of theinvention.

In the drawing, a log. is shown as rotatably mounted, with its axis inhorizontal relation, by means of spindles 11 disposed in bearingsupports 12 mounted on a base 13. Means, not shown, are provided forrotating the log in the direction of the arrow. The equipment thus fardescribed is conventional in veneer manufacture.

in accordance with the invention, a chipping knife assembly 14 iscarried by a holder 15 swingably mounted on a shaft 16 journalled inframe members 17 supported on guides 18. Means for swinging the knifeassembly into and out of engagement with log 10 may comprise a lever 19fixed to shaft 16. Lever 19 is pivotally connected to rod 20 of aircylinder 21 carried by bracket 22 on frame member 17.

Knife assembly 14 preferably comprises a row of uniformly spacedchipping tools 23 seated on the holder 15 and fixed thereto by means ofa clamping bar 24. Each tool 23 has a knife edge 25 preferablycomprising a major portion 25a of major extent extending in thegrainwise direction of the log and end portions 25b of minor extentextending angularly with respect to portion 25a. it will be apparentthat when the knife assembly is swung into engagement with the logsurface, the knife edges 25 will initially engage the log surface toproduce chips 26 and to form grooves in the log surface with interveningland areas.

produces chips of such characteristics that they may be.

Guides 18 are mounted for sliding movement on complementary guidemembers 27 fixed to a main base 28.

Also releasably fixed to guides 18, as by means of a latch 29 and latchlever 30, is a veneer blade linkage 31 to which is fixed a veneer bladeholder 32. A veneer blade 33 is fixedlyseated in the holder as by meansof a clamping plate 34. As shown, [blade 33 is vertically disposedwhereby its cutting edge 33a may engage the log in perpendicularrelation to the plane of the horizontal axis of the log. It will beobserved that the blade 33 engages the log at a level lower than thelevel of engagement of the chipping knives.

Means for adjustably moving the entire blade assembly as carried by theguides 18 in a direction towards andaway from the log comprises a wheel35 fixed to shaft 36, bevel gear 37 on shaft 36, meshing bevel gear 38on. lead screw 39 mounted in bearing 40, a split nut 41 fixed to guide18 and through which the screw 39 is threadedly received, and a nutrelease 42.

It will be apparent that certain parts of the device will be duplicatedon the other side of the machine (not shown) including guide 18, guidemember 27, frame member 17, lever 19, air cylinder 21, latch 29, latchlever 30, bevel gears 37,38 and lead screw 39.

In operation, a log is placed in the operative position described,suchlog having thereon its outer natural layer 43 the surface of whichis normally of highly uneven character.

With the log rotating and the chipping knife .assembly l4 and veneerblade 33 moved into suitably adjusted engagement therewith by means ofthe wheel 35, the chipping tools 23 produce the chips 26 and directlythereafter the blade 33 produces chips 44 by removal of the land areasresulting from the chipping operation of tools 23. It will be apparentthat the depth of cut of the tools 23 and of the blade 33 willbe equalsothat eventually a true cylindrical'surface will be formed on the log.At that time the cylinders 21 are actuated to swing the knife assembly14 out of engagement with the log and thereafter an acceptable veneersheet containing no waste sections will be produced by the blade 33.

The knife assembly 14 is preferably of the type described in CanadianPat. No. 676,095, which by reason of the knife edge configuration andapplication employed for the production of high quality pulp.

In any event, the chips produced are directly usable for pulp orparticle board manufacture without intermediate processing. Thus, moreeffective and efficient use of the waste product of veneer manufactureis achieved.

I claim:

1. In the manufacture of plywood veneer, a method of producing woodchips from the waste portion of logs which comprises rotating said logabout its axis, chipping the natural outer layer of said log to producea plurality of chips of a predetermined size range suitable for pulping,said chipping step including the steps of applying an aligned row ofchipping tools to said natural outer layer of said rotating log toproduce a plurality of chips and to form a series of grooves withintervening land portions in said layer, applying a veneer blade to saidlayer to remove said land portions and to produce chips therefrom,continuing said application of chipping tools and veneer blade untilsaid natural outer layer has been removed and said log has asubstantially true cylindrical surface and then withdrawing saidchipping tools from said log and engaging said cylindrical surface withsaid veneer blade to produce a sheet of veneer of substantially uniformthickness throughout its extent.

2. A method of producing wood chips as defined in

1. In the manufacture of plywood veneer, a method of producing woodchips from the waste portion of logs which comprises rotating said logabout its axis, chipping the natural outer layer of said log to producea plurality of chips of a predetermined size range suitable for pulping,said chipping step including the steps of applying an aligned row ofchipping tools to said natural outer layer of said rotating log toproduce a plurality of chips and to form a series of grooves withintervening land portions in said layer, applying a veneer blade to saidlayer to remove said land portions and to produce chips therefrom,continuing said application of chipping tools and veneer blade untilsaid natural outer layer has been removed and said log has asubstantially true cylindrical surface and then withdrawing saidchipping tools from said log and engaging said cylindrical surface withsaid veneer blade to produce a sheet of veneer of substantially uniformthickness throughout its extent.
 2. A method of producing wood chips asdefined in claim 1, including the step of rotating said log About itsaxis, and wherein said chipping step includes the step of applying acutting edge of each of said grooving tools to said log in a directionparallel to the grain of the log and at least one other cutting edge ofsaid tool to said log in a direction angularly of the grain of said log.